The human heart can suffer from various valvular diseases. These valvular diseases can result in significant malfunctioning of the heart and ultimately require replacement of the native valve with an artificial valve. There are a number of known artificial valves and a number of known methods of implanting these artificial valves in humans. Because of the drawbacks associated with conventional open-heart surgery, percutaneous and minimally-invasive surgical approaches are garnering intense attention. In one technique, a prosthetic valve is configured to be implanted in a much less invasive procedure by way of catheterization. For example, collapsible transcatheter prosthetic heart valves can be crimped to a compressed state and percutaneously introduced in the compressed state on a catheter and expanded to a functional size at the desired position by balloon inflation or by utilization of a self-expanding frame or stent.
A prosthetic valve for use in such a procedure can include a radially collapsible and expandable frame to which leaflets of the prosthetic valve can be coupled. The leaflets typically are made of biological materials such as pericardium valves or harvested valves. For improved function after deployment, it is often desirable to package and store such valves in the open (i.e., expanded) diameter inside a preserving solution up until the time the valve is mounted on a delivery device for implantation. Using this procedure, it may be necessary to crimp the valve in the operation room a few minutes before implantation, therefore precluding pre-crimping by the manufacturer. Thus many crimping devices are now shipped as a disposable accessory along with the valve and delivery system, thus increasing the importance of portability of such crimping devices.
Generally, conventional crimping devices operate by one of two methods. In one method, a stent is driven through a cone-like surface, which compresses the stent to a smaller diameter. For example, a static conical tube can be passed over a stent, thereby reducing its diameter. This method typically is used for crimping prosthetic valves having self-expanding metal frames (e.g., frames made of Nitinol), which are easily deformable. Self-expandable prosthetic valves typically are pushed from the conical tube of the crimping device into a sheath of a delivery apparatus, which retains the prosthetic valve in a radially compressed state. The second crimping method uses crimping jaws to create a cylinder-like surface that can change diameter. This method typically is used for crimping prosthetic valves having plastically-expandable frames (e.g., frames made of stainless steel or cobalt chromium alloys).
Self-expandable prosthetic valves typically have multiple connection features extending from the frame that form a releasable connection with the distal end of the delivery apparatus. Once the prosthetic valve has been deployed from the sheath inside the patient's body, the physician can release the connection between the delivery apparatus and the connection features of the prosthetic valve. A challenge in crimping self-expandable prosthetic valves involves the ability of the physician to easily and quickly crimp and load a prosthetic valve into a sheath of a delivery apparatus while aligning and connecting the connection features of the prosthetic with mating connection features of the delivery apparatus. There thus remains a need for an improved crimping device that addresses these and other disadvantages in the prior art.